Fusible extension cord plug



Nov. 1, 1949. A. G. BAUER FUSIBLE EXTENSION CORD PLUG Filed Nov. 8, 1946 2 Sheets-Sheet 1 Nov. 1, 1949. j A. G. BAUER 2,486,380

' FUSIBLE EXTENSION Conn PLUG Filed Nov. 8, 1946 2 Sheets-Sheet 2 {rake/r 6150449.

Patented Nov. 1, 1949 FUSIBLE EXTENSION CORD PLUG Arthur G. Bauer, Wantagh, N. Y., asalgnor to John H. Eggers, Great Neck, N. Y.

Application November 8, 1946,-SerialNo. roam 1 Claims. (cl. zoo-115.5)

This invention relates to improvements in a quick detachable connecting plug for electric extension cords and the like and to a fuse therefor. The invention is more particularly concerned with a safety attachment plug of this character adapted for use with various electrical appliances, such as lamps, flat-irons, toasters, and the like in which both legs of the extension cord circuit is protected against overload.

An object of the invention is therefore the provision of an improved electrical connection plug having a readily accessible and exchangeable fuse element associated therewith, whereby in the event of an overload or short. circuit in the plug circuit causing the fuse to burn, generally referred to as blow, the blown fuse element may be expeditiously replaced and thereby avoid the delays and inconvenience usually required to detect and then replace one ofa number of line circuit fuses which are often located in out of the way places and generally adjacent main line connections. with the consequent danger from errors.

A further object of the invention is the provision of an electric plug having a circuit controlling fuse mounted therein which may be examined and replaced only upon withdrawing the plug from an associated line socket and thereby breaking the plug circuit with the result that the fuse may then be readily examined and replaced without any attendant danger of burn or shock in so doing. a

A still further object of the invention is the provision of a one-piece plug having pairs of terminal contacts and the cord binding connection disposed within a recessed chamber in the prong end of the plug, and an insulated fuse member for bridging the contacts and being removably supported within the recessed chamber so as to provide a closure for the chamber and a protecting cover for the contacts and binding cord connections therein.

A still further object of the invention is the provision of an improved electrical plug comprising a body which is preferably constructed in one piece from any suitable insulating material, such as rubber, the body having a relatively deep recess in one end thereof with opposed walls of the recess provided with transversely alined slots opening through the ends of the walls, the plug also having a pair of spaced contacts at each of two opposite sides of the recess with one contact of each pair being integral with a socket engaging prong projecting outwardly from the recess, and the recess being adapted to receive a fusemember having end portions removably receivable in the slots for facilitating removal of the fuse by engagement of the end portions by the fingers.

A still further object of the invention is the provision of an improved fuse member having two pairs of spaced contact. elements at each side thereof, and a fuse link in electrical conof the casing and a pair of fuse links within the casing which are visible through the windows whereby the fuse is reversible.

Other objects and advantages of the invention will become apparent in the course of the following description, taken in connection with th accompanying drawings, wherein:

Figure 1 is an end view of the improved plug as observed from the left of Fig. 2, the view being on a substantially enlarged scale;

Fig. 2 is a vertical sectional view as observed in the plane of line 2-2, Fig. 1;

Fig. 3 is an elevational view of one of the plug prongs with its associated contact;

Fig. 4 is a side elevational view of a terminal contact for operative association with the contact of Fig. 3;

Fig. 5 is an elevational view of the structure of Fig. 4 as observed from the right thereof;

Fig. 6 is a top plan view of the terminal contact illustrated in Fig. 4;

Fig. "l is an elevational view of the plug as viewed from one side thereof;

Fig. 8 is an elevational view of the plug as viewed from an adjacent side thereof with the fuse member shown in operative association therewith;

Fig. 9 is a top plan view of the improved reversible fuse member adapted for operative association with the plug shown in Fig. 2;

Fig. 10 is a side view of the fuse member;

Fig. 11 is a plan view of one of the windows embodied in thefuse member;

Fig. 12 is a plan view of a separator embodiedin the fuse member;

one of the fuse links ber as observed in the plane of line iii-l5, Fig. 9,

the section being a substantially enlarged scale;

Fig. 16 is a part sectional view, of the plug corresponding to Fig. 2 showing the terminal contacts as viewed in the plane of line iB-Ii, Fig. 1, and showing the fuse member in operative position within the plug; I

Fig. 17 is a view corresponding to Fig. 1 but showing the fuse member in operative position within the plug.

All of the views'of the drawings as briefly described aboveshow the structure of double actual size except in Figs. 14 and 15 wherein the parts are shown approximately four times their actual size.

Referring now in detail to the drawings, P designates the improved electric cord plug, which, as shown, embodies a one-piece insulated body member I provided with a relatively deep and substantially rectangular recess II in one end thereof. The body is shown as further provided with a cord receiving aperture l2 opening through the opposite end thereof and which aperture opens into the recess H through an elongated portion 13. Thebody is further provided with slots Ila in opposed walls thereof opening into recess I I. While the body It may be constructed of any suitable insulation material, it is preferably constructed of rubber which is readily molded to desired shape and unbreakable in the event of impact with hard obiects.

This body I0 is also provided with a pair of socket engageable prongs I4 each of which is constructed from a strip of spring brass which is folded over in the provision of yieldable terminal portions l5 for frictional fit within the socket member, and the strip is further bent over in the provision of attaching portions I3 embedded in the body Ill. The prongs I4 each further includes a contact i1 disposed laterally of the prong proper, as is clearly indicated in Fig. 3. The contacts I! are preferably provided as continuations of the strips from which the prongs are formed.

As is indicated in Fig. l, the contacts ll are disposed at opposed sides of the body l0 relative to the respective prongs. A pair of terminal contacts it are provided at opposite sides of the respective prongs i4 and the terminal contacts include base portions i3 which are provided with tapped aperturm 20, formed by extruding the metal from the base portion. The tapped apertures are adapted to receive the cord binding screws 2| whose shanks may extend into the recesses 22, in the body Ill. The terminal contacts It further include doubled-overfoot portions 23 anchored in the body l0.

As is more clearly indicated in Fig. 2, the contacts I! and terminal contacts it, which are also preferably of spring brass, include similar rounded grooves 24 and 25 respectively for a purpose later to appear. Also as indicated in Fig. 1. the contacts I! and I3 are disposed in pairs adjacent the prongs l4 with the contacts of each pair disposed in alinement at opposite sides of the respective prong.

In the use. of the plug P an electric cord is entered into or molded in the plug through aperture I2I3 and as shown the two wires of the cord may be individually clampedto the terminal contacts I8 by means of the screws 2|. Instead of using the screw type binding post 2| it will be understood that any well known or approved terminal connections may be substituted, or the cord wits may be soldered directly to the terterminal (members l3, without altering the "invention.

Theconstruction of the plug, as described and shown in Fig. l, is such that current cannot be conducted from the prongs i4 to the cord wires through the terminal contacts I3 unless the contacts I7 and i3 adjacent each prong are placed in electrical circuit. As shown this is effected by my improved fuse member F illustrated in -uietail in Figs. 9 to 15 and shown in operative association with the plug in Figs. 16 and 17. This fuse member embodies a pair of superimposed mating shells 28 having reduced end portions 23a which are formed of suitable relatively rigid insulatiug material.

Each shell is provided with a pin 23 near one end thereof, and a pin receiving recess 29 adjacent the opposite end so that the pins will enter the recesses upon proper registration of the shells and thus act as a centering means for these parts. The shells also have registering plane faces 33 and centrally disposed elongated and relatively deep chambers 3| at the bottoms of which are disposed suitable windows 32 exposed through elongated sight openings 33 in opposed faces of the shells.

A fuse link 34 constructed of a suitable fusible alloy is disposed in engagement with the plane face 30' of each shell 26 and a separator 33, preferably constructed of mica or other suitable thin sheet insulation, is disposed between the fuse links 34, as is clearly indicated in Fig. 15.

Each of the fuse links 34 includes a reduced blow-out portion 33 which is arranged to be visible through a window 32 and each fuse link further includes legs 31 which are bent over as shown by the dotted lines 38 in Fig. 13. It

will be noted that the bent over leg portions of one link engage with lugs 39 at one side of one of the shells 26 and with thebent over portions of the'other link engaged with the lugs 40 of the other shell 26 at the opposite side thereof.

The entire fuse member is retained in assembled position by means of four brass clips 4!, which may be originally of the form shown in Fig. 14 having parallel end portions 42 and ridges 43 engageable with the grooves 24 and 25 of the contacts I1 and I8, when the fuse member is assembled with the plug. The clips 4| may be'assembled with the shells 26 by bending or snapping same over the end portions 42, as in Fig. 15, when all the elements of the fuse member are held in assembled relation, with the clips at one side of the fuse member in contact with the legs 31 of one of the fuse links 34, and with the clips at the other side of the fusemember in similar contact with the legs 31 of the other fuse link 34. I

The lugs 39 and 40 are provided with shoulders 33' and 40' formore accurate assembly of the fuse links 34 and the clips 4|, and as is more clearly indicated in Figs. 9 and 17,the lugs 33 and 40 provide recesses 45 for accommodating the prongs l4 when the fuse member F is operatively associated with the plug P.

While in Figs. 10 and 15 the shell faces 30 are shown in substantially spaced relation, they are in actual practice substantially in contact since the fuse links and separator are very thin and are shown here on an exaggerated scale merely for greater clarity of illustration.

It will accordingly be seen that the fuse member F embodies a pair of fuse links insulated .plug, as in Figs. 16 and 17, the contacts I! will be in electrical circuit with the terminal contacts l8. The fuse links 34 are preferably of less amperage than the main line fuses and the relatively large chambers 3| provide suilicient air space to meet approved blow-out tests. Eurthermore, since the fuse links are visible through the windows 32 their condition can be readily and safely ascertained, as above explained.

It is to be particularly noted that the fuse member F is insertable within and removable from the recess H by movement thereof axially of the plug, since the prongs l4 ride in the recesses 45 in the shells 26, and by reason of such mounting a fuse cannot be inspected or replaced until the plug is withdrawn from a wall or other line socket thereby avoiding any possible danger of burn and shock in examining or replacing the fuse member.

It is to be further noted that the fuse member provides an adequate cover for the bindingscrews and associated cord ends 2|, and since the re;- duced shell portions 26a seat in the slots Ha in the assembled position of the fuse member, the ends of such reduced portions may be grasped by Y the fingers and the fuse member be easily with- What I claim and desire to secure by U. 8.

Letters Patent is: V

1. A fuse member comprising a pair of shells of insulating material and having cooperating flat walls, a pair of fuse elements disposed be-. tween the walls and insulated from each other. a pair of metallic contact clips disposed at each side of said member and engaged with said shells for holding said fuses between said walls, and each of said fuses being in contact with a pair of said clips.

2. A fuse member according to claim 1 wherein said fuses are insulated from each other by a sheet-like separator of insulating material disposed between the fuses.

3. A fuse member according to claim 1 wherein each of said shells is provided with a chamber opening through the outer wall of the shell, and a fuse viewing window within each chamber and beneath said outer wall.

4. A fuse member comprising a pair of shells of insulating material and each having an elongated chamber opening through a flat face portion thereof and each of said shells provided with a pair of spaced lugs at each side thereof with tie: lugs of one shell adapted to register provided'with, a pair of legs, the legs of one fuse element being engaged with lugs on one shell and the legs of the other fuse element being engaged with lugs on the other shell at the opposite side of the member, and metallic clips engaged with the lugs and said fuse legs for holding the parts in assembled relation.

5. An attachment plug comprising a body having a recess in one end thereof, a pair 'of binding posts in the base of said recess, a pair of spaced spring contacts associated with each binding post within said recess and extending in opposite directions to opposite sides of said recess, a chambered member comprising a pair of shells of insulating material and having cooperating flat walls, a pair of fuse elements disposed between the walls and insulated from each other, a pair of metallic contact clips disposed at each side of said member and engaged with said shells for holding said fuse elements between said walls, each of said fuse elements being in contact with a pair of said clips, said chambered member being of a size to substantially fill saidrecess and overlie said binding posts, and frictionally engage said clips disposed at each side of said member with said spaced spring contacts.

6. An electric plug comprising a one-piece rubber body member having a cord receiving aperture opening through one end thereof, a relatively deep recess in the other end of said member communicating with said aperture,'terminals supported by said body member at the bottom of said recess, prongs supported by the body member and projecting therefrom through said recess, a fuse carrying cover for said recess removably supported therein between said prongs and connecting the terminals within the recess, said fuse carrying cover comprising a pair of shells of ,insulating material and having cooperating flat walls, a pair of fuse elements disposed between the walls and insulated from each other, a pair of metallic contact clips disposed at each side of said member and engaged with said shells for holding said fuse elements between said walls, a transparent window in the wall of one of said shells, and each of said fuse elements having leg portions in contact with a pair of said clips and an intermediate portion 1 underlying said window.

REFERENCES CITED The following'references are of record in the file of this patent:

STATES PATENTS Williams, Jr. et a1. Oct. 28, 1947 

